1. Field of the Invention
The invention relates to a method for processing cut edges of a blank member (“sleeve”) made from packaging material, in particular paper/plastics composite material, the cut edges of which are open from above and/or below, by applying a processing medium and a device for carrying out this method and a packaging sleeve which is processed in accordance with this method.
2. Description of Related Art
During the production of multi-layer composite packagings, for example, beverage packages, different methods are used.
For example, packages are produced from individual blanks of paper/plastics composite material. In this instance, individual blanks are first obtained from a reel of composite material, and these are subsequently provided with a longitudinal seam. The longitudinal seams are produced by folding and sealing the composite material in such a manner that a product which is intended to fill the package cannot come into contact with an open edge of the composite material. Such contact could lead to a softening of the packaging material and to a contamination of the product with which it has been filled.
The further processing of packaging sleeves which are produced in this manner, that is to say, the single-sided closing at the upper or lower side of the subsequent package, the sterilisation, the filling and reclosure, is mostly carried out directly in the filling machine.
When the package is produced, the sleeve is first closed at the upper or lower side. Subsequently, the inner side of the package is cleaned and optionally disinfected, before the container which is closed at one side is supplied to the aseptic zone of the filling machine. There, the package is filled and closed. The package is subsequently given its definitive shape. Such a sterilisation method is described, inter alia, in DE 32 35 476 A1.
Regardless of the production method, the closure of the package is generally carried out by pressing and sealing the package material edges, for example, by means of a sonotrode and an anvil. Other methods for closing the packaging are also known, for example, electromagnetic induction or hot air together with mechanical pressing.
The closure of a filled packaging sleeve which is open at one side involves the risk that, in particular when sealing with ultrasound, dust can be thrown out of the packaging material from the open cut edges and it can contaminate both the aseptic region and the open packages.
From the prior art, various methods are known for sealing the edges of packaging blank members of cardboard. The sealing is intended to prevent the penetration of fluid into internal edges of the package after the packaging has been produced.
The generic DE 30 11 630 A1 discloses a method for processing package end faces with an oil which is introduced into the end faces. In this instance, the oil is introduced into all the pores to the greatest possible extent and can be partially polymerised by the effect of heat. The viscosity thereby increases.
WO 96/18544 A1 describes a method for sealing edges of packages with wax, plastics material, adhesive or melt adhesive. The sealing is in this instance applied by means of a nozzle, by means of immersion or spraying. Subsequently, the sealing can be hardened by means of heat.
From U.S. Pat. No. 3,187,480 A, it is known to compress a stack of cardboard blank members and to immerse them in a hot bath of impregnation solution in order to protect the cut edges. Glycine and castor oil are disclosed as an impregnation solution.